By Jeff DannerJeff has worked in both the chemical and biotech industries and is the veteran of thousands of science debates at cocktail parties and holiday dinners across the nation. In his Common Science blog, Jeff aims to make technological and scientific concepts accessible to all.

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Last week in “2012 The Year Without a Winter” I explained that in order to limit atmospheric carbon dioxide to 450 parts per million, the goal set during the 2009 UN Climate Conference in Copenhagen, we need to leave half of the known fossil fuel reserves in the ground. I also noted my skepticism that, barring a collapse of the global economic system, we actually would leave them in the ground. With that background in hand, let’s discuss the proposed Keystone XL Pipeline project which, if constructed, would be a 2,873 mile long pipeline from the oil sands in Alberta, Canada to refineries in Illinois, Oklahoma, and Texas.

If you had to pick the top candidate among the fossil fuel reserves that you wanted to leave in the ground to meet the Copenhagen target, you would be hard pressed to pick anything other than the oil sands. Long, long ago the hydrocarbons which are now contained in the Canadian oil sands were deep underground and were liquid. The geology of central Alberta allowed them to migrate upward to their current shallow depths where they now saturate sand and clay deposits near the surface. This turned out to be a rather bad environment for the hydrocarbons. Mixing with the sand and clay resulted in the dissolution of metals, like mercury, lead, and selenium, into the hydrocarbon phase. Also, being near to the surface brought the hydrocarbons into contract with bacteria which have been breaking them down for the last couple of hundred million years.

As a result of bacterial action, the hydrocarbons in the sand and clay, even with all of the sand and clay are removed, are not really liquids anymore but rather a semi-solid called bitumen. (I have to be careful with the terminology here. Bitumen is, by definition, a liquid in the same way that glass is a liquid. Give it a few hundred years and it will slump a bit.)

The bitumen in the sand is a terrible fuel source. So bad that, until recently, it was not even included in the calculations of fossil fuel reserves. Let me try to illustrate the drawbacks of bitumen by reviewing the process of converting it to gasoline.

First you strip mine the oil sands from the ground (see the picture at the top of the page) using the largest earthmoving equipment ever built by mankind, which requires a lot of energy, fossil fuel energy. (Note: At present about 150 square miles of Alberta looks substantially like this picture.)

Then you need to heat the mixture of bitumen, sand, and clay to 900 oF, which requires a lot of energy.

Then you need to remove the sand and clay, which requires a lot of energy.

Then you need to remove the metals from the bitumen, which . . .

Then you need to remove the nitrogen from the bitumen, which . . .

Then you need to removed the sulfur from the bitumen, which . . .

Then in a high temperature, high pressure operation, you need to hydrogenate the bitumen, which really uses a lot of energy.

Now that you have gone through all this effort and energy consumption to clean and upgrade the bitumen to convert it to gasoline, you’ve got to transport it to a refinery which requires making it into a liquid. To liquefy the bitumen, you need to both heat it and dilute it with a solvent. This sort of diluted bitumen is what would flow through the proposed Keystone XL pipeline if it is constructed.

We already know that the energy balance for the Canadian oil sands is going to go from bad worse with time. Approximately 20% of the oil sands in Alberta are shallow enough to be collected by strip mining. The other 80% would need to be recovered by what are referred to as in situ techniques which involve injecting steam, solvent, and hot air deep into the ground. It’s possible that the in situ recovery techniques will be less devastating to the environment compared to strip mining, but they will require 50% more energy consumption to get the bitumen from the ground to the refinery.

If we are not going to leave the bacteria-degraded, metal-laden, sulfur-contaminated, low-energy-content the oil sands which require massive energy inputs to extract in the ground, I see no reason to believe that we will leave ANY of the fossil fuel reserves in the ground. This will put us on the path to a future with some of the more extreme impacts from global warming. Some of these impacts are hard to predict, some not. Perhaps the easiest to conceptualize is the impact of a rise in sea level of several meters. Most the world’s great cities, much of the infrastructure of modern civilization, and critical portions of our farmland are along the waterfront. Submerging these assets will have a devastating impact on humanity.

I understand that these blogs are taking a bit of a dour turn of late. However, these are the types of energy and environmental challenges we need to be discussing and confronting during a presidential election year, especially when one of the parties considers global warming to be a hoax.

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